Drainage pumps are generally used for the drainage of accumulated liquid. One example, would be the drainage of water from a sump pit, which is commonly found in the basement of a house or other similar structure. The sump pit is simply a hole dug in the ground to collect water that enters a basement via perimeter drains funneling into the pit or from natural ground water in the earth. However, drainage pumps can also be used for removing liquid from ejector pits/systems, water collection wells, process water holding tanks, or the like.
Drainage pumps can be installed anywhere where flooding or liquid levels are seen as a problem. These pumping systems can be critical for pumping liquid to a location where it no longer presents a hazard. Given the important function provided by these pumps, there is a constant need to monitor and maintain the overall pump systems; particularly, if the pump is located in a harsh environment. Additionally, the lack of maintenance can drastically shorten the life of the pump or even require premature pump replacement.
More recent pump control systems include liquid level monitoring and alarm indication, which implement the use of mechanical and electronic floats. U.S. Pat. No. 4,187,503 to Walton and U.S. Pat. No. 6,149,390 to Fisher et al. are examples of systems that implement the use of mechanical floats. The mechanical floats sense the liquid level by being urged to a predetermined level in a sump pit by the rising liquid. Once the predetermined level is reached, an electrical contact is closed energizing an alarm circuit.
On the other hand, U.S. Pat. No. 5,314,313 to Janesky discloses the use of an electronic float. The electronic float includes two spaced apart electrodes placed at a predetermined level in the sump pit, wherein the rising liquid level provides the electrical connection between the electrodes thereby energizing the alarm circuitry. Although, these references appear to provide adequate alarm indications for undesirable water levels, they provide little monitoring and indication for protecting the pump and pump motor.
U.S. Pat. No. 5,324,170 and U.S. Pat. No. 5,545,012 both to Anastos et al. disclose pump monitoring and control systems. However, both of these systems are directed primarily to overcoming deficiencies in liquid level monitoring systems. For example, instead of using mechanical or electronic floats, these systems rely on monitoring certain operating characteristics of the pump to determine the presence of liquid in the sump pit. Power to the pump can then be controlled based on the results of this monitoring. Although these systems monitor operating characteristics of the pump, their primary purpose is to avoid the use of liquid level monitoring to control the operation of the pump. In fact, there is limited use of alarm indications for identifying adverse operating conditions that affect the operation of the pump and pump motor.
U.S. Pat. No. 6,676,382 to Leighton et al. is also directed to a pump monitoring control system that includes indications for certain operating conditions of a pump. However, similar to U.S. Pat. No. 4,187,503 to Walton and U.S. Pat. No. 6,149,390 to Fisher et al., the system here implements the use of a mechanical float. Therefore, a substantial amount of monitoring and alarming systems are used for detecting problems commonly associated with mechanical floats, not for protecting the pump or the pump motor.
Thus, there appears to be a need for improved monitoring, indication and control of a pump system.